1. Field of the Invention
The present invention provides a genus of optionally substituted isoxazoline compounds and related methods of use and pharmaceutical compositions. The compounds have MIF (macrophage migration inhibitory factor) antagonist activity. Specifically, the MIF antagonists are useful in methods for treating a variety of diseases involving inflammatory activity or pro-inflammatory cytokine responses, such as autoimmune diseases, asthma, arthritis, multiple sclerosis, ARDS (acute respiratory distress syndrome) and various forms of sepsis and septic shock, and other conditions characterized by underlying MIF responses including, for instance, tumor growth and neovascularization.
2. Background of the Technology
Macrophage migration inhibitory factor (MIF) is one of the earliest described cytokines, and is an immunoregulatory protein with a wide variety of cellular and biological activities (for reviews see: Swope, et al., Rev. Physiol. Biochem. Pharmacol. 139,1-32 (1999); Metz et al., Adv. Immunol. 66,197-223 (1997); and Bucala, FASEB J. 14, 1607-1613 (1996)). Originally, MIF was found to be secreted by activated lymphoid cells, to inhibit the random migration of macrophages, and to be associated with delayed-type hypersensitivity reactions (George et al., Proc. Soc. Exp. Biol. Med., 111, 514-521 (1962); Weiser, et al., J. Immunol. 126, 1958-1962 (1981); Bloom et al., Science, 153:80-82 (1966); David, Proc. Natl. Acad. Sci. USA, 56, 72-77 (1966). MIF was also shown to enhance macrophage adherence, phagocytosis and tumoricidal activity (Nathan et al., J. Exp. Med., 137, 275-288 (1973); Nathan, et al., J. Exp. Med., 133, 1356-1376 (1971); Churchill et al., J. Immunol., 115, 781-785 (1975)). Unfortunately, many of the early MIF studies used mixed-culture supernatants that were shown later to contain other cytokines, such as IFN-γ and IL-4, that also have macrophage migration inhibitory activity (McInnes et al., J. Exp. Med., 167, 598-611 (1988); Thurman, et al., J. Immunol., 134, 305-309 (1985)). The availability of recombinant MIF has allowed for confirmation of these biological activities, and for the identification of additional activities.
Recombinant human MIF was originally cloned from a human T cell library (Weiser et al., Proc. Natl. Acad. Sci. USA, 86, 7522-7526 (1989)), and was shown to activate blood-derived macrophages to kill intracellular parasites and tumor cells in vitro, to stimulate IL-1β and TNFα expression, and to induce nitric oxide synthesis (Weiser, et al., J. Immunol., 147, 2006-2011 (1991); Pozzi, et al., Cellular Immunol., 145, 372-379 (1992); Weiser, et al., Proc. Natl. Acad. Sci. USA, 89, 8049-8052 (1992); Cunha, et al., J. Immunol., 150, 1908-1912 (1993)). While the conclusions available from several of these early reports are confounded by the presence of a bioactive mitogenic contaminant in the recombinant MIF preparations used, the potent pro-inflammatory activities of MIF have been established in other studies that do not suffer from this complicating factor (reviewed in Bucala, The FASEB, Journal 10,1607-1613 (1996)).
More recent MIF studies have capitalized on the production of recombinant MIF in purified form as well as the development of MIF-specific polyclonal and monoclonal antibodies to establish the biological role of MIF in a variety of normal homeostatic and pathophysiological settings (reviewed in Rice, et al., Annual Reports in Medicinal Chemistry, 33, 243-252 (1998)). Among the most important insights of these later reports has been the recognition that MIF not only is a cytokine product of the immune system, but also is a hormone-like product of the endocrine system, particularly the pituitary gland. This work has underscored the potent activity of MIF as a counter-regulator of the anti-inflammatory effects of the glucocorticoids (both those endogenously released and those therapeutically administered), with the effect that the normal activities of glucocorticoids to limit and suppress the severity of inflammatory responses are inhibited by MIF. The endogenous MIF response is thus seen as a cause or an exacerbative factor in a variety of inflammatory diseases and conditions (reviewed in Donnelly, et al., Molecular Medicine Today, 3, 502-507 (1997)).
MIF is now known to have several biological functions beyond its well-known association with delayed-type hypersensitivity reactions. For example, as mentioned above, MIF released by macrophages and T cells acts as a pituitary mediator in response to physiological concentrations of glucocorticoids (Bucala, FASEB J., 14, 1607-1613 (1996)). This leads to an overriding effect of glucocoticoid immunosuppressive activity through alterations in TNF-α, IL-1β, IL-6, and IL-8 levels. Additional biological activities of MIF include the regulation of stimulated T cells (Bacher et al., Proc. Natl. Acad. Sci. USA, 93, 7849-7854 (1996)), the control of IgE synthesis (Mikayama, et al., Proc. Natl. Acad. Sci. USA, 90, 10056-10060 (1993)), the functional inactivation of the p53 tumor suppressor protein (Hudson et al., J. Exp. Med., 190, 1375-1382 (1999)), the regulation of glucose and carbohydrate metabolism (Sakaue et al., Mol. Med., 5, 361-371 (1999)), and the attenuation of tumor cell growth and tumor angiogenesis (Chesney et al., Mol. Med., 5, 181-191 (1999); Shimizu, et al., Biochem. Biophys. Res. Commun., 264, 751-758 (1999)).
MIF shares significant sequence homology (36% identity) with D-dopachrome tautomerase. This led to the discovery that MIF has enzymatic activity and catalyzes the tautomerization of the non-physiological substrates D-dopachrome (Rosengren et al., Mol. Med., 2,143-149 (1996)) and L-dopachrome methyl ester (Bendrat et al., Biochemistry, 36, 15356-15362 (1997). Additionally, phenylpyruvic acid and p-hydroxyphenylpyruvic acid (Rosengren, et al., FEBS Letter, 417, 85-88 (1997)), and 3,4-dihydroxyphenylaminechrome and norepinephrinechrome (Matsunaga et al., J. Biol. Chem., 274, 3268-3271 (1999), are MIF substrates, although it is not known if tautomerization of any of these agents comprises a natural function for MIF.
The three-dimensional crystal structure of human MIF reveals that the protein exists as a homotrimer (Lolis, et al., Proc. Ass. Am. Phys., 108, 415-419 (1996) and is structurally related to 4-oxalocrotonate tautomerase, 5-carboxymethyl-2-hydroxymuconate, chorismate mutase, and to D-dopachrome tautomerase (Swope, et al., EMBO J., 17, 3534-3541 (1998); Sugimoto, et al., Biochemistry, 38, 3268-3279 (1999). Recently, the crystal structure has been reported for the complex formed between human MIF and p-hydroxyphenylpyruvic acid (Lubetsky, et al., Biochemistry, 38, 7346-7354 (1999). It was found that the substrate binds to a hydrophobic cavity at the amino terminus and interacts with Pro-1, Lys-32, and Ile-64 in one of the subunits, and with Tyr-95 and Asn-97 in an adjacent subunit. Similar interactions between murine MIF and (E)-2-fluoro-p-hydroxycinnamate have been reported (Taylor, et al., Biochemistry, 38, 7444-7452 (1999)). Solution studies using NMR provide further evidence of the interaction between p-hydroxyphenylpyruvic acid and Pro-1 in the amino-terminal hydrophobic cavity (Swope, et al., EMBO J., 17, 3534-3541 (1998)).
Mutation studies provide convincing evidence that Pro-1 is involved in the catalytic function of MIF. Deletion of Pro-1 or replacement of Pro-1 with Ser (Bendrat, et al., Biochemistry, 36,15356-15362 (1997)), Gly (Swope, et al., EMBO J., 17, 3534-3541 (1998)), or Phe (Hermanowski-Vosatka, et al., Biochemistry, 38, 12841-12849 (1999)), and addition of an N-terminal peptide tag to Pro-1 (Bendrat, et al., Biochemistry, 36, 15356-15362 (1997)) abrogated the catalytic activity of MIF in assays using L-dopachrome methyl ester and p-hydroxyphenylpyruvic acid. A similar loss in activity was found by inserting Ala between Pro-1 and Met-2 (Lubetsky et al., Biochemistry, 38,7346-7354 (1999). The connection between the enzymatic and biological activities, however, remains unclear. The Pro to Ser MIF mutant showed glucocorticoid counter-regulatory activity (Bendrat, et al., Biochemistry, 36,15356-15362 (1997)) and was fully capable, as was the Pro to Phe mutant, of inhibiting monocyte chemotaxis (Hermanowski-Vosatka et al., Biochemistry, 38, 12841-12849 (1999). In contrast, the Pro to Gly MIF mutant was greatly impaired in its ability to stimulate superoxide generation in activated neutrophils (Swope et al., EMBO J., 17, 3534-3541 (1998). These results suggest that the biological activity of enzymatically inactive MIF mutants may be dependent not only on the nature of the mutation, but also on the assay that is used to assess biological function.
There is a need in the art to discover and develop small organic molecules that function as MIF inhibitors (e.g., antagonists) and further posses the benefits of small organic molecule therapeutics versus larger, polymeric protein (e.g., antibody) and nucleic acid-based (e.g., anti-sense) therapeutic agents. The therapeutic potential of low molecular weight MIF inhibitors is substantial, given the activities of anti-MIF antibodies in models of endotoxin- and exotoxin-induced toxic shock (Bernhagen et al., Nature, 365, 756-759 (1993); Kobayashi et al., Hepatology, 29,1752-1759 (1999); Calandra et al., Proc. Natl. Acad. Sci. USA., 95, 11383-11388 (1998); and Makita et al., Am. J. Respir. Crit. Care Med. 158, 573-579 (1998), T-cell activation (Bacher et al., Proc. Natl. Acad. Sci. USA., 93, 7849-7854 (1996), autoimmune diseases (e.g., graft versus host disease, insulin-dependent diabetes, and various forms of lupus) including rheumatoid arthritis (Kitaichi, et al., Curr. Eye Res., 20, 109-114 (2000); Leech, et al., Arthritis Rheum., 42, 1601-1608 (1999), wound healing (Abe, et al., Biochim. Biophys. Acta, 1500, 1-9 (2000), and angiogenesis (Shimizum, et al., Biochem. Biophys. Res. Commun., 264, 751-758 (1999). Low molecular weight anti-MIF drugs exhibiting such activities may offer clinical advantages over neutralizing antibodies and nucleic acid-based agents because they may be orally active or generally more easily administered, have better bioavailabilities, have improved biodistributions, and should be much cheaper to produce. Prior to the present invention, the only published report of potent low molecular weight MIF inhibitors concerned some commonly found long chain fatty acids that reversibly inhibited the dopachrome tautomerase activity of mouse MIF (Bendrat et al., Biochemistry, 36, 15356-15362 (1997). These fatty acids were never tested for their effects in biological assays of MIF activity.
U.S. Pat. No. 4,933,464 to Markofsky discloses a process for forming 3-phenylisoxazolines and 3-phenylisoxazoles and related products.
U.S. Pat. No. 6,114,367 to Cohan et al. discloses isoxazoline compounds which are inhibitors of tumor necrosis factor (TNF). The isoxazoline compounds are said to be useful for inhibiting TNF in a mammal in need thereof and in the treatment or alleviation of inflammatory conditions or disease. Also disclosed are pharmaceutical compositions comprising such compounds.
Curuzu et al., Collect. Czech. Chem. Commun., 56: 2494-2499 (1991) discloses 3-substituted phenyl-4,5-dihydroisoxazoleneacetic acids, including 3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazolineacetic acid and 3-(4-methoxyphenyl)-4,5-dihydro-5-isoxazolineacetic acid, and shows that the first of these two compounds is devoid of antiinflammatory activity, while the second is dramatically reduced in such activity compared to the parent compound that was unsubstituted in the para position of the phenyl ring, in a carageenin-induced edema assay in the rat paw.
Wityak et al., J. Med. Chem., 40: 50-60 (1997) discloses isoxazoline antagonists of the glycoprotein IIb/IlIa receptor.
Eichenger, et al., Synth. Commun. 27 (16): 2733-2742 (1997) discloses [3-(4-methoxy-phenyl)-4,5-dihydro-isoxazol-5-yl]-acetic acid.
Eichinger, et al., Synth. Commun. 28(13): 2457-2466 (1998) discloses [3-(4-methoxy-phenyl)-4,5-dihydro-isoxazol-5-yl]-acetic acid and the methyl ester thereof.
Kleinman et al., “Striking effect of hydroxamic acid substitution on the phosphodiesterase type 4 (PDE4) and TNF alpha inhibitory activity of two series of rolipram analogues: implications for a new active site model of PDE4”. J. Med. Chem. 41(3): 266-270 (1998), discloses inter alia the following compounds: [3-(3-cyclopentyloxy-4-methoxy-phenyl)-4,5-dihydro-isoxazol-5-yl]-acetic acid and the methyl ester thereof, as well as [3-(3-cyclopentyloxy-4-methoxy-phenyl)-4,5-dihydro-isoxazol-5-yl]-N-hydroxy-acetamide.
U.S. application Ser. No. 09/625,829, filed Jul. 26, 2000, which is hereby incorporated herein by reference in its entirety, discloses quinone-related compounds having MIF inhibitor activity. U.S. application Ser. No. 09/699,258, filed Oct. 27, 2000, which is hereby incorporated herein by reference in its entirety, discloses amino acid/benzaldehyde Schiff base compounds having MIF inhibitor activity.